Just thinking out loud...
MANY years ago, I remember using mental "flash cards" to learn hand patterns at bridge. This is a common learning tool for getting used to the numbers at bridge. 4432, 5431, 6322. Stuff like that.
The next time this ever entered my mind was in learning parity signals.
Recently, however, I started thinking as to whether there are other ways to categorize patterns. Whether this would add any benefit or not is unclear. But, just getting a grasp on pattern type thinking might lead itself somewhere.
Here's an example of what I mean.
What do hands like 4432, 4441, 5440, and even 4333 have in common with some hand patterns like 6421, 6430, 5422, and 5431?
Well, nothing obvious. However, let's assume that the first group has a common theme, namely that the shortest suit is in one of the majors. Then, let's assume that the second group has a common theme, namely that the shortest suit is the same major as in the first group, the longest suit is diamonds, and the second-longest suit the other major. Now any similarities?
I'll pick one short major, the short spades example:
Group One: 2443, 2434, 2344, 1444, 0445, 0454, 0544, 3433
Group Two: 1462, 2461, 3460, 0463, 2452, 3451, 1453
Now, do you see any pattern similarities?
There is nothing numerically similar, at least not that I can see, other than the similarities forced into the example. However, from a bridge perspective, these two pattern groups are "related" in that all are appropriate for a takeout double, if an equal-level-conversion call is systemically allowed.
This is no great observation, in its own right. However, thinking about these groupings in a sort of brainstorming effort leads to some thoughts. (Might work better with pot.) Like, I notice that hands with primary clubs and secondary other-major do not fit into this grouping, which means that they are "left out," possibly needing a "solution." I think out loud about the "physical" qualities of this situation, where "weight" seems easily spread out or grouped at the top BUT with primary weight just below the top. It seems that the interests of bidding goals, coupled with practicalities and safeties, force certain "weight" tendencies to patterns suitable for certain approaches.
One might, then, plausibly devise a methodology where a certain call handles "convenient pattern holdings" but an alternative handles "inconvenient pattern groupings."
Imagine, for simple example, an overcalling structure over 1NT where immediate calls show "convenient grouping holdings," such as with, say, Cappelletti, whereas a double might simply show "inconvenient pattern holdings." After a 2C relay from Advancer, the Doubler might indicate some core feature of some "inconvenient pattern group." For instance, 2D after the relay might show some hand with diamonds plus a shorter major. Or, 2D might also cover some other diamond-focused "inconvenient pattern group" as well, if there is a way to describe the inconvenient pattern group because we know all of the diamond-focused entries into that pattern group. Of course, I don't know that group right now -- hence the thought experiment.
I mean, we all have these hands that pop up where we look at the hand and gasp at the complete lack of options. If we could somehow find that these "ugh!!!" hands have some "mechanics" causing the difficulties, we might somehow figure out a cure along the lines of some artificial capture technique.
Consider an example. Maybe a 2NT response to a major opening might actually serve better (than other ideas typically used) as a "flag" of a trouble pattern hand, with 3C asking to explain, and Responder identifying the difficult pattern.
Just a thought, perhaps.